Plan merger - ADP test deadline

[fiona1]

A 401(k) plan with a 1/1 plan year merges into another 401(k) plan that has a 10/1 plan year. The merger occurs on 10/1/08.

The 1/1 plan runs an ADP test from 1/1/08 to 9/30/08 and it fails. Are refunds due 12 months from 9/30/08? Or are they due 12 months from 12/31/08?

[MWeddell]

12 months from the last day of the plan year, which is 9/30/2010. It seems to me that the merger creates a short plan year for the plan that was merged out of existence.

The situation is ambiguous enough that you might wait to read other posters' opinions though.